A prospective research method that compares the outcomes of the experimental group and the control group after intervention to determine the effectiveness of the intervention.

Forward-looking

randomization

Balance

Interventions

Clinical Trials

Field trials (individual trials)

individual

community intervention trial

real experiment

Quasi-experiment

The basic unit that receives a treatment factor, also called an experimental subject

Basic conditions

Factors that are applied to subjects and whose effects need to be observed and elucidated in clinical experiments are also called intervention factors.

The effect of processing factors on the subjects' reactions and outcomes is also the core content of experimental research.

Principles of observing indicators

placebo control

Blank control

Experimental control

self control

Standard control

simple random grouping

stratified randomization

Cluster randomization

Repeat of entire experiment

Repeat with multiple subjects

Repeated observations of the same subject

1. The inclusion conditions, exposure conditions and results of the research subjects can be Conduct standardized assessments; 2. Increase the comparability of the experimental group and the control group through random grouping; 3. Synchronous observation, external factors have little impact on the results

1. Design, implementation and analysis are relatively complex; 2. Since the conditions of the research subjects are strictly controlled, the population under study may lack representativeness, which affects the inference of the experimental results to the overall population; 3. Since the research subjects are humans, subject compliance is not easy to ensure, and sometimes medical ethics disputes may arise.

Randomized controlled trial (RCT)

non-randomized concurrent controlled trial

crossover design trial